The invention relates to threaded fasteners in general, and more particularly to improvements in female (internally threaded) fasteners commonly known as nuts. Still more particularly, the invention relates to improvements in nuts with enlarged bases which obviate the need for washers; such nuts are known as flange nuts. Still more particularly, the invention relates to improvements in so-called castellated or castle nuts wherein a torque receiving intermediate section is disposed between a so-called clamping section or castle and a flange or base.
It is already known to solidly reshaping or massively form simple nuts by resorting to cold- and/or hot-extrusion; for example, such nuts can be used to separably secure wheel hubs to the axles of motor vehicles. It is also known to massively form castellated nuts and to provide such nuts with bases or flanges which are caused to bear against selected objects, e.g., wheels, in response to rotation of their torque receiving sections by the working end of a wrench or another suitable torque applying tool while the nut mates with an externally threaded fastener which is affixed to an axle and extends through a hole of a wheel hub for use in an automobile or another vehicle. The torque receiving section can be of one piece with or it can be separately produced and thereafter affixed to a flange. As a rule, the castellated clamping section is provided with a conical internal thread which tapers in a direction toward the axis of the nut and away from the flange. On the other hand, the torque receiving section is provided with a cylindrical internal thread which is complementary to the external thread of a screw, bolt or another male threaded fastener. Still further, it was already proposed to provide the castellated clamping section with a set of axially parallel recesses.
The conventional mode of making a combined castellated flange nut involves the making of a cylindrical internal thread in the clamping section, the making of a cylindrical internal thread in the torque receiving section, a material removing step which involves the formation of axially parallel slots in the clamping section, and a following step of bending the zones of the clamping section between neighboring slots radially inwardly at the junctions with the torque receiving section. This last mentioned step results in conversion of the originally cylindrical internal thread of the clamping section into a substantially frustoconical thread whose conicity is not very pronounced. The material removing operation which is being resorted to for the making of axially parallel slots in the partially finished clamping section results in the development of burrs or fins which extend radially inwardly into the central passage of the clamping section. Such burrs or fins must be removed in a separate step which contributes to the cost and to the length of the interval elapsing for the making of a nut. If the burrs or fins are not removed (or are not completely removed) from the interior of a clamping portion, they cause the development of pronounced localized friction which, in turn, causes extensive wear upon the external thread of a male fastener and/or the internal thread of the nut.